Conventionally, there has been known a failure restoration method which enhances a user's convenience by resuming a display, after a screen display apparatus has been restored from a failure, starting from contents which had been displayed on the screen display apparatus when the failure occurred (for example, refer to patent document 1).
FIG. 9 is a block diagram showing main parts of a display system which realizes a conventional failure restoration method disclosed in the patent document 1. In FIG. 9, the display system comprises a display controller 902, a display apparatus 903, and a monitor 904.
The display controller 902 schedules a display for various contents received externally, which is outputted to the display apparatus 903 while switching the various contents to be displayed on a screen. When switching the contents to be displayed on the screen, the display controller 902 transmits to the monitor 904 the contents to be displayed as screen switching information.
The display apparatus 903 has a screen such as a display and displays the contents outputted from the display controller 902 on the screen.
The monitor 904 monitors the display controller 902, detects a failure occurring on the display controller 902, and restores the failed display controller 902. More specifically, the monitor 904 receives the screen switching information outputted from the display controller 902 and stores in an internal memory the received screen switching information as sequential logging information. When the monitor 904 cannot receive the screen switching information within a predetermined period of time, the monitor 904 determines that the display controller 902 is in a state of a failure and restarts the display controller 902. And the monitor 904 reads from the internal memory latest screen switching information outputted from the display controller 902, temporarily stores the read latest screen switching information as failure history information in another area of the internal memory, and prepares to transmit the stored failure history information to the displayer controller.
After restart processing has been completed, the display controller 902 transmits to the monitor 904 a signal notifying that a normal operation starts. The monitor 904 determines, by receiving the notifying signal transmitted from the display controller 902, that the display controller 902 starts the normal operation. And the monitor 904 transmits to the display controller 902 the failure history information temporarily stored in the internal memory.
The display controller 902 receives the failure history information transmitted from the monitor 904 and based on the received failure history information, sequentially transmits to the display apparatus 903 contents which had been displayed on the display apparatus 903 when the failure occurred, by using the display contents which had been stored before the failure occurred. The display apparatus 903 displays on the screen the contents transmitted from the display controller 902.
In the conventional failure restoration method, after the failed display controller 902 has been restored, the contents which had been displayed when the failure occurred are displayed on the display apparatus 903.
Patent document 1: Japanese Laid-Open Publication No. 2002-108657 (pages 3-4, FIG. 1)